I have the same problem with Tecumseh lawnmower. I wonder if the
little clip on the needle valve could cause it to hang if not turned
the correct way? Diagram shows the closed U facing forward and the
open end facing towards the rear. The diagram also shows a small
O-ring between the bowl and the stem. I'll bet mine came off when I
removed the bowl.
Oh well, I installed a shut off valve and just turn it off as I head in
for the old barn.